Personally, I would rather start by using the most rudimentary example. Then, I would use DisplayA3D.createImage and addImage to add the three quads into the scene. I would expect to get a deterministic behaviour. After that, I would try to play with the zbuffer, the buckets or the drawing/addition order to obtain exactly the expected result. By the way, "JogAmp's Ardor3D Continuation doesn't behave exactly as Java3D" isn't a bug.